When linking a library libA with a library libB using libtool, if libB.la
exists, libtool will add all libraries libB.la refers to (dependency_libs
field) to the linker command line and store them in the dependency_libs
field of libA.la. So everything that subsequently links with libA will also
link to these extra libraries. This causes too much overlinking.
This commit modifies Mk/Uses/libtool.mk so it empties the dependency_libs
field in .la libraries during staging. However, because .la libraries have
very limited use when dependency_libs is empty it makes sense to completely
remove them during staging.
So with this commit USES=libtool is modified to remove .la libraries and a
new form (USES=libtool:keepla) is introduced in case they need to be kept
(dependency_libs is still emptied).

* Update the glib to 2.34.3 and gtk20 to 2.24.17 and gtk30 to 3.6.4 which
are the latest stable releases.
* Update vala to the newest stable release 0.18.1, also update a few ports
in the gtk/gnome stack.
* The c++ bindings ports for glib, atk, gconf, etc, have now USE_GNOME toggles.
* Remove pkg-config run depends from glib20 and freetype2. This doesn't
eliminate pkg-config run dependency completely, a second phase is needed
and is planned.
* Support for .:run. and .:build. for USE_GNOME components was added.
Currently only libxml2 and libxslt support this mechanism.
* Updates of the telepathy stack and empathy.
* Trim makefile headers, convert ports to new options, trim off library
versions for some ports.
* Fix other ports so they build with the new glib version.
Thanks to miwi and crees for helping out with some exp-runs.
Approved by: portmgr (miwi & bapt)
Obtained from: gnome team repo

Presenting GNOME 2.28.1 for FreeBSD. The official release notes for this
release can be found at http://library.gnome.org/misc/release-notes/2.28/ .
Officially, this is mostly a polishing release in preparation for GNOME 3.0
due in about a year.
On the FreeBSD front, though, a lot went into this release. Major thanks
goes to kwm and avl who did a lot of the porting work for this release.
In particular, kwm brought in Evolution MAPI support for better Microsoft
Exchange integration. Avl made sure that the new gobject introspection
repository ports were nicely compartmentalized so that large dependencies
aren't brought in wholesale.
But, every GNOME team member (ahze, avl, bland, kwm, mezz, and myself)
contributed to this release.